Taxonomy: Remove redundant caching from get_all_category_ids(), deprecated in favor of get_terms() in [28679].

The `all_category_ids` cache key it relied on was removed in [5555] and never repopulated, causing invalid or unexpected results when using a persistent object cache.

Props itowhid06, johnjamesjacoby.
Fixes #48176.
Built from https://develop.svn.wordpress.org/trunk@46810


git-svn-id: http://core.svn.wordpress.org/trunk@46610 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/deprecated.php

@@ -1286,16 +1286,13 @@ function get_category_children( $id, $before = '/', $after = '', $visited = arra
 function get_all_category_ids() {
 	_deprecated_function( __FUNCTION__, '4.0.0', 'get_terms()' );
 
-	if ( ! $cat_ids = wp_cache_get( 'all_category_ids', 'category' ) ) {
-		$cat_ids = get_terms(
-			array(
-				'taxonomy' => 'category',
-				'fields'   => 'ids',
-				'get'      => 'all',
-			)
-		);
-		wp_cache_add( 'all_category_ids', $cat_ids, 'category' );
-	}
+	$cat_ids = get_terms(
+		array(
+			'taxonomy' => 'category',
+			'fields'   => 'ids',
+			'get'      => 'all',
+		)
+	);
 
 	return $cat_ids;
 }